I am running a Windows 7 KVM on CentOS 7. The Windows 7 guest resolutions are all 4:3 or 16:10
My monitor is 1920x1080, but KVM/Spice/Whatever is only offering me 1920x1200.
I don't know what part of the puzzle is causing this. I downloaded some drivers from here, http://www.linux-kvm.org/page/WindowsGuestDrivers but none of them seemed to be video drivers and when I try to update the adapter or display drivers Windows tells me I already have the best driver.